Field of the Invention
The invention relates to an integrated circuit and a method of manufacturing the same, and particularly relates to a semiconductor device and a method of manufacturing the same.
Description of Related Art
High-voltage semiconductor devices are widely used in high-voltage AC-DC converters, LED drivers, and other fields. With the rise of environmental awareness, the high-voltage semiconductor devices having high conversion efficiency and low standby power consumption get more attention. Thus, a high-voltage start-up circuit (HV start-up circuit) and a pulse width modulation (PWM) circuit are usually integrated in a single chip to achieve the effect of energy saving.
In the prior art, a power resistor is usually used as the high-voltage start-up circuit. However, energy consumption is still continued after the power resistor starts up the pulse width circuit, such that the energy consumption is increased, which is not suitable for green products. In recent years, a high-voltage junction field-effect transistor (HV JFET) or a depletion mode double-diffused metal oxide semiconductor (depletion mode DMOS) is used as the high-voltage start-up circuit. The high-voltage junction field-effect transistor is turned off after starting up the pulse width circuit, so as to reduce the energy consumption. However, to withstand the voltage of up to several hundred volts, the size of the high-voltage junction field-effect transistor is larger, which limits the design flexibility of saturation current of the high-voltage junction field-effect transistor. Therefore, how to provide a high-voltage junction field-effect transistor, which can provide an adjustable and wide saturation current to meet different circuit needs without changing any of process conditions, is an important issue.